Institute of Standards and Industrial Research of Iran (ISIRI) defines standards for the following Iranian pistachio products:

In-Shell Pistachio Nuts: ISIRI 15 4th revision

Mechanically Opened Pistachio Nuts: ISIRI 4919 1st revision

Closed Shell Pistachio Nuts: ISIRI 4921 1st revision

Pistachio Kernels: ISIRI 218 4th revision

Split Pistachio Kernels: ISIRI 3639 1st revision

Green Peeled Pistachio Kernels: ISIRI 4631 1st revision

Pistachio Oil: ISIRI 6655 no revision

Pistachio Paste: ISIRI 5691 no revision

Pistachio Powder: ISIRI 9636 no revision

The following table contains an abridged version of specifications for the five pistachio grades set out by ISIRI Standard 15 (4th Revision January 2009) for in-shell pistachio nuts (including raw dried and roasted pistachios):

Variety: Iranian pistachios are categorized into two categories according to their shape: long pistachios, where the ratio of the length to the largest diameter is more than 1.52; and round pistachios, where the ratio of the length to the largest diameter is less than 1.52.

Non-uniformity of variety: The percentage of round pistachios in a sample of long pistachios or vice versa.

Non-uniformity of Size: Ratio of the total weight of the 10 largest nuts in a sample of 100 nuts to the weight of the smallest 10.